25 research outputs found
Corona discharge in a cylindrical triode charger for unipolar diffusion aerosol charging
No full textDevelopment and Evaluation of a Faraday Cup Electrometer for Measuring and Sampling Atmospheric Ions and Charged Aerosols
No full textPerformance evaluation of an electrometer system for ion and aerosol charge measurements
No full textApproach to characterization of a diode type corona charger for aerosol size measurement
No full textAn overview of differential mobility analyzers for size classification of nanometer-sized aerosol particles
No full textSize classification of nanoparticles is an important process in the electrical mobility particle size analyzer. The differential mobility analyzer (DMA) is one of the most commonly used devices for classifying and measuring nanometersized aerosol particles between 1 nm to 1 μm in diameter, based on their electrical mobility. The DMA can be described as an assembly of two concentrically cylindrical electrodes with an air gap between the walls. In the DMA, air and aerosol flows enter from one end, pass through the annulus and exit the other end. An electric field is applied between the inner and outer electrodes. Particles having a specific mobility exit with the monodisperse air flow through a small slit located at the bottom of the inner electrode. These particles are transferred to a particle counter to determine the particle number concentration. In the past several decades, there have been numerous extensive studies and developments on the DMA. Nonetheless, they are different in terms of specific applications, construction, particle size range, as well as time response and resolution. The purpose of this article is to provide an overview of the state-of-the-art existing cylindrical DMAs for aerosol particle size classification as well as for the generation of monodisperse aerosol in nanometer size range. A description of the operating principles, detailed physical characteristics of these DMAs, including the single-channel and multi-channel DMAs, as well as some examples of applications to nanotechnology are given
Use of electrostatic precipitation for excess ion trapping in an electrical aerosol detector
No full textComparative Study on Electrical Discharge and Operational Characteristics of Needle and Wire-Cylinder Corona Chargers
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Numerical Computation of Fluid Flow and Aerosol Transport in a Long Electrical Mobility Spectrometer
Get PDFSize distribution of submicron airborne particles can be effectively determined using electrical mobility
technique. In this study, a numerical computation model for prediction of fluid flow and aerosol transport in a
long column, electrical mobility spectrometer (EMS) has been developed. The internal 3D structure of an EMS
[Intra and Tippayawong (2009), Korean J. Chem. Eng., 26(1), 269] was employed to simulate the complex flow
patterns and aerosol particle trajectories in the EMS, including the swirling flow developed near the sheath air
inlet slit. The incompressible Navier-Stokes equations were numerically calculated for the gas flow and particle
trajectories, with a commercial computational fluid dynamics software package, FLUENT 6.3. The calculated
results were found to agree well with previously published results in the literature. Prediction of fluid flow and aerosol transport was particularly useful in the EMS design and development
